it started as a tweet from justin bieber. katy perry did it. cookie monster. everyone wanted to sing their own version of this song. you can't get it out of your head. so once you did it you wanted to get on youtube and get it out of your head into everyone else's. >> like "gangnam style" with more than a million views. >> korean rapper psy. it's the pony dance. >> what fast fates me about the story is this thing was out on the internet for a while before it really started to go viral and it's word how this stuck catches at a moment. >> that's exactly right. one of the things we saw was twitter and facebook detective tating. it was on every talk show, every award show, everything you can think of after starting a tweet on your phone. you were like this video is funny, aisle press it. it is. it's as funny as they said. >> from tweets to facebook to social media, we move to books now, and it's hard to argue that fifty shades of grey was not the big book publishing phenomenon. >> it's not whether or much i loved it or how freaked out i was to see people reading t